High and low temperature environmental test chamber> is a common test equipment. Through the cyclical changes of high temperature, low temperature and humidity, it can simulate the extreme weather environment more realistically and obtain accurate test results.
In various tests, the high and low temperature chamber environmental test chamber is widely used, and it contains many types of products. It is the necessary hardware experimental equipment for simulating the environmental adaptability test of products under various ambient temperatures. It is used to test the quality of mobile phones, plastic products, metals, food, chemicals, building materials, medical care, aerospace and other products. It can be said that our lives are closely related to it. For example, the mobile phone we use in our daily life, as a fast-response electronic product, requires very sensitive electronic components in order to make a quick response. At this time, the high and low temperature test chamber needs to strictly screen the electronic components. Although strict screening will lose part of the cost at the beginning, because electronic components have very strict requirements on temperature and humidity, once the temperature and humidity change and do not meet the requirements, the service life of electronic components will gradually decrease.
The principle of high and low temperature environmental test chamber:>
High and low temperature environmental test chamber> The heating process is to generate heat after the wires in the heating system are energized, and then transfer the heat generated by the air circulation system to the working room through circulating air to achieve the purpose of heating. Because of its fast heating speed and high heat, it has been widely used. Some users usually have high requirements on heating rate and high temperature range. Based on this principle, wires can be added and the control system adjusted accordingly to meet this requirement.
Next is cooling. The core equipment of this process is the compressor. The compressor compresses low-temperature and low-pressure gas into high-temperature and high-pressure gas, and converts it into liquid through the condenser. The evaporator evaporates these liquids into low-temperature and low-pressure gas and enters the compressor, so the cycle is continuous. , absorbing a large amount of heat and finally completing cooling. The heat generated by the compressor is carried away by the fan. Energy control devices are often added to equipment to control refrigeration energy and energy consumption in order to achieve the purpose of producing maximum temperature with minimum energy consumption and reduce costs.
In addition to cooling and heating, the equipment should also pass through the humidity control system, humidification or dehumidification to meet the necessary humidity during the work process.
The high and low temperature environmental test chamber can mainly carry out the following test methods:>
1. High temperature test
Purpose of the test: To assess the adaptability of the test samples for storage or use under high temperature conditions. Applied to instruments, equipment, etc. that work in high temperature environments such as tropical weather or steel factories.
Test equipment: high and low temperature(Damp heat) test chamber.
Test conditions: generally select a constant temperature stress and holding time.
Preferred common temperature: 200°C, 175°C, 155°C, 125°C, 100°C, 85°C, 70°C, 55°C, etc.;
The preferred commonly used test times are: 2h, 16h, 72h, 96h, etc.
2. Low temperature test
Purpose of the test: To assess the suitability of the test samples for storage or use under low temperature conditions. It is often used in the type test of products in the development stage, the screening test of components, etc.
Test equipment: high and low temperature (humid heat) test chamber
Test conditions: generally select a constant temperature and test time.
Preferred commonly used temperatures are: -65°C, -55°C, -40°C, -25°C, -10°C, -5°C, +5°C, etc.;
The preferred commonly used test times are: 2h, 16h, 72h, 96h, etc.
3. Constant temperature and humidity test
Purpose of the test: To assess the adaptability of the product for use and storage under hot and humid conditions, to observe the influence of the test sample in a constant temperature, no condensation, and high humidity environment for a specified time, and to evaluate the effect of the test sample on the resistance to heat and humidity degradation in an accelerated manner.
Test equipment: constant temperature and humidity chamber.
Test conditions: test temperature; test humidity; test time.
The preferred and commonly used temperatures/humidities are: 40℃, 85%; 40℃, 93%; 85℃, 85%, etc.;
The preferred and commonly used test times are: 48h, 96h, etc.
4. Temperature and humidity cycle test
Test purpose: Suitable for determining the suitability of test samples for use and storage under hot and humid conditions where temperature cycles change and condensation occurs on the surface.
Test equipment: high and low temperature (humid heat) test chamber.
Test conditions: selected temperature, humidity, number of cycles, temperature change rate, and duration.
High and low temperature test standards:>
GB_T 2423.2-2008 Environmental testing of electrical and electronic products Part 2: Test methods Test B: High temperature
GBT 2423.1-2008 Environmental testing of electrical and electronic products Part 2: Test methods Test A: Low temperature
IEC 60068-2-2 Basic Environmental Test Procedure Part 2-2: Test Test B: Dry Heat
IEC 60068-2-1: 2007 Environmental Testing of Electrical and Electronic Products: Low Temperature
The impact of high and low temperatures on electronic (plastic) products:>
1. High temperature may overheat the product, affecting its safety and reliability, or even damage it. Such as:
1. The grouting glue used for insulation or sealing melts and flows, and the grease melts and flows.loss, resulting in tower damage
2. Change the properties of materials
3. The elastic or mechanical strength of the elastic element is reduced, shortening the service life of the product
4. Accelerate the deterioration and aging process of polymer materials and insulating materials, and shorten the service life of products.
Second, the influence of low temperature on mechanical, electrical, and electronic products is multifaceted, and varies with the characteristics of the product's energy, degree and auxiliary structure, such as:
1. Freeze the electrolyte and cause electrolytic capacitors and batteries to fail to work normally
2. The viscosity of lubricating oil increases, or even condenses and freezes, which affects the starting performance of the product
3. Affect the normal startup of electronic products and increase the error of the instrument
4. Make the material brittle, such as plastic and steel, which are prone to brittle crack damage at low temperature, the hardness of the rubber material increases, and the elasticity decreases.
The basic requirements that the product should meet after the high and low temperature test:>
The product quality after the high and low temperature test is generally inspected according to the product technical conditions or the requirements stipulated in the technical agreement. For example, the impact of high temperature environment on the performance of motor products is manifested in the increase in resistance of conductive materials, resulting in changes in current. For motors with precision requirements, it will also affect the accuracy. Therefore, after the high temperature test, the insulation resistance should be measured in the test box, and its value should not be lower than 5MΩ, and other performances of the motor should be tested at the same time. In general, after the temperature test, if the product can meet the following basic requirements, it is considered that the product meets the high and low temperature requirements.
1 There is no damage, deformation and other defects on the surface of the product. If the surface is coated, there should be no peeling, blistering or discoloration of the coating.
2 For plastic parts, there are no cracks, blisters and deformations on the surface.
3 Rubber products have no aging, bonding, softening and cracking.
4 There is no flow phenomenon in the welding part of the product parts.
5. Product performance data and structural functions meet the requirements of technical conditions and requirements, and there should be no other defects that hinder the normal operation of the product.
The high and low temperature humidity and heat alternating test chamber meets IEC60068-2-1 (IOS2423.1), IEC60068-2-2 (IOS2423.2), IEC60068-2-78, IEC60598-1, IOS2423 .17, IOS5170.2, IOS5170.5 and other standards. It can be used in CFL/LED lighting industry testing and meets the IES LM-80-08 standard. It can also be used in electrical products, electronic components, materials and other industries.